It can be reassuring for clients to see changes to their website online, before they publish it for real on a public facing site. A private viewing is just what you need.
Edditt lets you set up a preview URL field on any editing page, which grants users an online preview. This invaluable feature gives users a real time visualisation of the changes they are making on a specific item.
Private viewing eliminates the worry that an important client might visit the site during updates. Clients can tweak and check and tweak again, until they are totally happy.